Late Pliocene to Late Pleistocene; Recent.
Southern Florida to North Carolina.
First Available Description (from Conrad, 1867, p. 14-15):
"Description. — Subtriangular; very inequilateral; anterior side somewhat produced, acutely rounded at the extremity.
Amphidesma aequalis, Say, Tuomey and Holmes. — Pliocene Foss. of S. Carolina, p. 93, pi. 23, fig. 3.
Observations. — This Miocene fossil has hitherto been considered identical with Say's aequalis, but it differs in attaining a larger size, and more especially in having a much wider cartilage fosset and more elongated or produced anterior side."
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